I’ll try and provide some insight as no one has responded..The old rule of thumb was 1 snail per 1 gallon. However a lot of people will say that was a number made up by fish stores to sell more product. In my honest opinion what you have listed does seem a bit excessive.
I’ve never owned any sea urchins but they are supposed to be a great addition to any CUC. I would assume they do the job of multiple snails when eating.
My tank is a bit smaller than yours at 32 gallons and every tank is different. That being said I feed pretty heavily. I only have 1 Nassarious, 1 fighting Conch, a small blue legged hermit crab and 2 Astrea snails. I have a healthy population of bristle worms. As well as some Asterina starfish. Between a daily glass cleaning with a mag float and a weekly water change everything is kept squeaky clean.
I know Asterina starfish are heavily debated in the hobby. There are said to be 32 different varieties of Asterina. The ones I have do not eat my corals and seem to be a great addition to CUC.
I was mislead some years ago saying they should be eradicated..after having gotten rid of all of them I began to miss the lil guys. I asked my roommate if I could take some of his to reseed the tank and have never experienced any issues. After 4 years of keeping the Asterina without issue I’m going to go ahead and say this variety does not eat corals.